N-acetylneuraminic acid is known to be produced by extraction or decomposition, and by using enzymes or microorganisms.
An example of a known method by extraction is extraction from a nest of sea swallows, etc. [Carbohydr. Res., 56, 423 (1977)].
An example of a known method by decomposition is decomposition of colominic acid which is an N-acetylneuraminic acid polymer produced by Escherichia coli, etc. [J. Biochem., 82, 1425 (1977)].
Known methods utilizing enzymes include: methods using N-acetylneuraminic acid aldolase, pyruvic acid and N-acetylmannosamine [J. Am. Chem. Soc., 110, 6481 (1988); J. Am. Chem. Soc. 110, 7159 (1988)], methods using N-acetylneuraminic acid aldolase, pyruvic acid and N-acetylglucosamine under alkaline conditions [Enzyme Microbiol. Technol., 20, 393 (1997); U.S. Pat. No. 5,665,574], methods using N-acetylneuraminic acid aldolase, N-acetylglucosamine 2-epimerase, pyruvic acid and N-acetylglucosamine [Angew. Chem. Int. Ed. Eng., 30, 827 (1991); Carbohydr. Res., 306, 575 (1998)]; and methods using N-acetylneuraminic acid synthase, phosphoenolpyruvic acid and N-acetylmannosamine [Japanese Published Unexamined Patent Application No. 4961/98; Glycobiology, 7, 697 (1997)].
An example of a known method using microorganisms is a method utilizing microorganisms which have the ability to produce proteins having N-acetylneuraminic acid aldolase, N-acetylneuraminic acid synthase and N-acetylglucosamine 2-epimerase activities (Japanese Published Unexamined Patent Application No. 136982/01).
However, except the method utilizing microorganisms, the above methods for producing N-acetylneuraminic acid require complicated operations or expensive materials, or involve insufficient conversion efficiency.
Furthermore, further development of an economical and efficient method for producing N-acetylneuraminic acid is desired with respect to the method utilizing microorganisms.